Verification Tests Research Articles

Research on the influence of gas types on the pumping performance of dry Roots vacuum pump

With the advancement of technology, dry vacuum pumps are widely used in aerospace, semiconductor, chemical and pharmaceutical and scientific equipment due to their clean and oil-free advantages. Usually the pumped medium contains different types of gases, dry Roots vacuum pumps are prone to unstable performance, which can adversely affect process efficiency. To investigate the influence of gas types on the pumping performance of Roots vacuum pump, experimental research was conducted on self-designed dry vacuum pump theoretical verification platform and test pump. The gas mixture of 70 % nitrogen and 30 % helium was tested using 2-lobe, 3-lobe and 5-lobe Roots while numerical simulations were conducted on air, nitrogen, helium and hydrogen. The experimental results indicate that the gas type affects the pumping speed of the Roots pump. In addition, the numerical simulation results show that hydrogen has the greatest influence on the pumping performance of the Roots; the pumping speed shows ‘W’ type fluctuation in one cycle when the 3-lobe Roots pumps hydrogen. The pumping speed of the 5-lobe Roots is most affected by changes in gas types. This study is of guiding significance for the application and design of dry Roots vacuum pumps in different process environments.

RUL Prediction of Rolling Bearings Based on Multi-Information Fusion and Autoencoder Modeling

As an important part of industrial equipment, the safe and stable operation of rolling bearings is an important guarantee for the performance of mechanical equipment. Aiming at the problem that it is difficult to characterize the running state of rolling bearings, this paper mainly analyzes and processes the vibration signals of rolling bearings, extracts and fuses multi-information entropy, and monitors the running state of rolling bearings and predicts the remaining useful life prediction (RUL) through test verification. Firstly, in view of the difficulty in characterizing the bearings running state characteristics, a rolling bearings running state monitoring method based on multi-information entropy fusion and denoising autoencoder (DAE) was proposed to extract the multi-entropy index features of vibration signals to improve the accuracy of feature extraction, and to solve the problem of not obvious information representation of a single feature indicator and missing information in the feature screening process. Secondly, in view of the problems of low prediction accuracy and poor robustness and generalization in traditional RUL models, a rolling bearings RUL model combining convolutional autoencoder (CAE) and bidirectional long short-term memory network (BiLSTM) was proposed. The introduction of convolution operation made CAE have the feature of weight sharing, reducing the complexity of the model. Finally, the XJTU-SY data set was used to verify the constructed model. The results show that the condition monitoring model established in this paper can accurately evaluate the running state of the rolling bearing and accurately locate the failure time. At the same time, the residual life prediction model can realize the residual life prediction of most data sets, and has good accuracy and robustness.

Analysis of the Suitability of Ultrasonic Testing for Verification of Nonuniform Welded Joints of Austenitic-Ferritic Sheets.

The purpose of the presented research was to determine the suitability of using ultrasonic testing (UT) to inspect heterogeneous, from a material point of view, welded joints on the example of the joints of a ferritic steel element with elements made of an austenitic steel. The echo technique with transverse (SEK) and longitudinal wave heads (SEL) addressed this issue. Due to the widespread use of 13CrMo4-5 and X2CrNiMo17-12-2 steel grades in the energy industry, they were selected as the test materials for the study. The objects of the presented research were welded joint specimens with thicknesses of 8, 12, and 16 mm and dimensions of 300 × 300 mm, made using the 135 metal active gas (MAG) process with the use of the Lincoln 309LSi wire-a ferritic-austenitic filler material. The stages of the research task were (1) making distance-amplitude curve (DAC) patterns from the test materials; (2) preparation of specimens of welded joints with artificial discontinuities in the form of through-holes; (3) performing UT tests on welded joints with artificial discontinuities using heads with 60° and 70° angles for the transverse wave and angle heads for longitudinal waves with similar beam insertion angles; (4) selection, by radiographic testing (RT), of welded joint specimens with natural discontinuities in the form of a lack of sidewall fusion; (5) performing UT tests on welded joints with natural discontinuities, using heads as welded joints with artificial discontinuities. It was found that (1) the highest sensitivity of discontinuity detection was obtained by performing tests on the ferritic steel side, which is due to the lower attenuation of the ultrasonic wave propagating in ferritic steel compared to austenitic steel; (2) the best detection of discontinuities could be obtained using a longitudinal ultrasonic wave; (3) there is a relationship between the thickness of the welded elements, the angle of the ultrasonic beam introduction, and the effectiveness of discontinuity detection.

气压式玉米精量排种器递进性清种装置设计与试验

In order to improve the sowing performance of air-pressure maize dense planting high-speed precision seed-metering device and reduce the occurrence of multiple and missed seeds phenomenon, a seed-cleaning mechanism with progressive seed scraper was designed. The structure and working principle of the seed-metering device and seed-cleaning mechanism are described, the mechanical model before and after the excess seed enters the seed cleaning area is established, and the design parameters of the key components of the seed-cleaning mechanism are determined through the method of theoretical analysis. The experiments of single-factor and multi-factor are conducted with seed clearing angle, operating speed, positive pressure value of blower as influencing factors, and with qualified index, miss index, multiple index as the experimental indexes. The results show that the optimal seed-clearing performance parameter combination of the seed-cleaning mechanism is seed-clearing angle of 0.024°, operating speed of 10 km/h, positive pressure value of 6.0 kPa, verification test of the parameter combination of the qualified index of 98.11%, multiple index of 1.44%, miss index of 0.45%. In the comparative experiment, the qualified index of the device with seed-cleaning mechanism increased by about 2.3% compared to the device without seed-cleaning mechanism, and the multiple index decreased by about 2.2%. The seed-cleaning mechanism is reasonably designed to meet the seed clearing operation requirements of air-pressure maize dense planting high-speed precision seed-metering device.

Combined Multi-Omics Analysis Reveals the Potential Role of ACADS in Yak Intramuscular Fat Deposition.

The Yak (Bos grunniens) is a special breed of livestock predominantly distributed in the Qinghai-Tibet Plateau of China. Intramuscular fat (IMF) content in beef cattle is a vital indicator of meat quality. In this study, RNA-Seq and Protein-Seq were respectively employed to sequence the transcriptome and proteome of the longissimus dorsi (LD) tissue from 4-year-old yaks with significant differences in IMF content under the same fattening conditions. Five overlapping genes (MYL3, ACADS, L2HGDH, IGFN1, and ENSBGRG00000000-926) were screened using combined analysis. Functional verification tests demonstrated that the key gene ACADS inhibited yak intramuscular preadipocyte (YIMA) differentiation and proliferation, promoted mitochondrial biogenesis gene expression, and increased the mitochondrial membrane potential (MMP). Furthermore, co-transfection experiments further demonstrated that interfering with ACADS reversed the effect of PPARα agonists in promoting lipid differentiation. In conclusion, ACADS potentially inhibits lipid deposition in YIAMs by regulating the PPARα signalling pathway. These findings offer insights into the molecular mechanisms underlying yak meat quality.

Sowing depth stability analysis and test verification of no-tillage planter parallel 4-bar row unit

The sowing depth stability and consistency of the no-tillage planter, particularly the high-speed operation, are poor. A reason for this is that the structure and parameter selection of no-tillage planter row unit profiling mechanism are unreasonable. The stability and consistency of sowing depth is beneficial when the upper and lower links of the parallel 4-bar profiling mechanism (PFPM) are parallel to the ground, but this principle is not satisfied on the uneven no-till soil. To improve the stability of gauge wheels downforce (GWD) and sowing depth of no-tillage planter row unit. The variation law of spring additional downforce (SAD) with tilt angle of parallel 4-bar profiling mechanism (PFPM) and connection offset of spring is discussed by constructing the steady state analysis matrix equation of PFPM. Additionally, the influence of tilt angle of PFPM and SAD on the stability of the sowing depth was analyzed. Based on the single factor control variable test method, bench and field tests were conducted. The test results show that the SAD increases nonlinearly with the increase in the degree of tilt of PFPM from downward to upward. Under the condition that four springs are installed and the tilt angle of PFPM is between (−20°–20°), the maximum SAD is 485.95 N, 1236.64 N, and 2258.05 N when the spring connection offset is 44 mm, 79 mm, and 115 mm, respectively. When the tilt angle is 8° upward, the GWD increases by 429 N, 575 N, and 984 N, GWD stability increases by 42.31 %, 56.16 %, and 50.29 %, and ditching depth stability increases by 30.00 %, 12.50 %, and 30.00 % compared with that of the control group at the sowing speed of 8, 10, and 12 km/h, respectively. At the sowing speed of 10 km/h, when the PFPM is operated with spring-free and additional springs, the average GWD increases by 353 N, and the stability of GWD and ditching depth increases by 34.38 % and 20.00 %, respectively. The results showed that the tilt upward of PFPM and SAD were beneficial to improve the stability of the GWD and sowing depth of the no-tillage planter row unit. The results not only verify the correctness of theoretical analysis, but also provide theoretical basis for the design and application adjustment of high-speed no-tillage planter.

Automatic Excavation System with Multiple Excavators in the Pneumatic Caisson Method

In this study, we propose an automated excavation system for pneumatic caisson construction using either a single excavator or multiple excavators. The system divides the work area among the excavators and manages the transition of occupied states in shared areas to reduce the risk of collisions. Additionally, the Laplace potential method is employed for path planning to avoid collisions with equipment inside the caisson. The system also includes a mechanism for disposing of soil outside the caisson by dumping it into an earth bucket. To confirm the effectiveness of the proposed method, verification tests were conducted: one using a single excavator in a narrower-than-usual caisson, and another using two excavators in a test field. These tests demonstrated the method’s effectiveness.

Development of hybrid landing gear for OMOTENASHI surface probe

This study presents technologies of the triple hybrid landing gear for the OMOTENASHI(Outstanding Moon exploration Technologies demonstrated by Nano Semi-Hard Impactor) spacecraft, which consists of an airbag, a crushable material as a shock absorber, and an impact resistance structure. The inflated airbag has capability to possibly mitigate impact acceleration at the instant of landing and submergence into regolith that covers a planetary surface. The crushable material with lattice structures, manufactured by a metal 3D printer, serves a dual purpose: it dissipates kinetic energy and controls the impact acceleration at landing by compressing itself within a designed deceleration distance. Further, in the impact resistance structure, the protective object is filled with resin and hollow glass beads, and the impact resistance is improved while the weight reduction is maintained. This paper provides the technical details such as the required specification, verification test results, and assembly result of the surface probe as the smallest lander of the OMOTENASHI spacecraft.

Modular Open Chamber Stand for Biomass Densification Using the Example of Miscanthus × Giganteus Greef Et Deu

This article presents a modular open chamber stand which simulates the densification process that occurs in a single channel of a pelletising die. The results of the verification tests confirmed the suitability of this stand for determining the optimal geometry of the channel. The test material was the biomass of Miscanthus × giganteus which is considered to be a difficult material for pressure densification; therefore, it was decided that it would be a good material for verifying the stand. The stand consists of four modules: an introductory section with a diameter of D = 12 and 10 mm, a conical part with an angle of α = 10°, 20°, 30°, 40°, a cylindrical part with lengths L = 5, 15, 25, 35, 45 mm and diameter d= 8 mm and a pellet receiving module. The stand is able to heat the densification channel. Individual modules can be assembled into test combinations; this results in a change in channel geometry without the necessity to manufacture many singular channels. The optimum geometry of the channel for miscanthus with a moisture content of 13%, densified at 100 °C was determined. It should be a channel with D = 10 mm, α = 40° and L = 18 mm.

Noncontact magnetically coupled piezo-electromagnetic rotary energy harvester

Aiming at the problems of high environmental vibration frequency, low output power and short life of the energy harvesters, a noncontact magnetically coupled piezo-electromagnetic rotary energy harvester is proposed in this paper. It consists of a base, a top cover, a rotating body, a cantilever beam, a permanent magnet, a coil, a hollow tube and a clamp. The novel hybrid harvester can produce both piezoelectric and electromagnetic energy at the same time, and in addition, it can efficiently generate electricity at low ambient vibration. Moreover, the piezoelectric material is protected from direct collision by noncontact magnetic coupling excitation. In order to conduct a comprehensive study on the performance of the piezoelectric-electromagnetic rotary energy harvester, we set up a rotating test platform to carry out systematic test verification, and to determine the distance between the permanent magnet and the rotating body and the number of permanent magnets on the rotating body. The test results show that when four permanent magnets are uniformly pasted on the rotating body and the rotating speed is 775 r/min, the piezoelectric and electromagnetic output power are 3.4 mW and 2.69 mW, respectively, and the total hybrid output power is 6.09 mW.

Pengaruh Current Ratio, Return on Asset, Debt to Equity Ratio dan Firm Size terhadap Price to Book Value pada Perusahaan Consumer Cyclicals Subsektor Apparel and Luxury Goods yang Terdaftar di Bursa Efek Indonesia Periode 2015-2023

The purpose of this research is to ascertain how the price to book value of consumer cyclical companies in the apparel and luxury goods subsector listed on the Indonesia Stock Exchange is affected by return on assets, current ratio, debt to equity ratio, and business size between 2015 and 2023. An approach to verification and description is combined with a quantitative methodology in this study. Statistical tests for verification include the traditional assumption test, multiple linear regression, Pearson correlation coefficient, determination coefficient, and hypothesis testing with partial and simultaneous tests (t and f tests). The Financial Reports of 72 Companies in the Apparel and Luxury Goods Subsector of Consumer Cyclicals Companies provide the sample data. sampling with nonprobability purposive sampling. Version 26.0 of SPSS is utilized as a data processing tool. Price to Book Value is not impacted in any way by the study's findings regarding Current Ratio, Return on Asset, Debt to Equity Ratio and firm size. The study's findings concurrently demonstrated that Price to Book Value was significantly impacted by Current Ratio, Return on Asset, Debt to Equity Ratio, and Company Size

Gamified Mobile App (MobERAS) for Telemonitoring Patients in the Postoperative Period Based on the Enhanced Recovery after Surgery Program: Development and Validation Study.

Digital technology and gamified apps can be useful in the health care context. Gamification uses technology to influence users' actions and motivations through experiences that resemble games. Patient adherence to the enhanced recovery after surgery (ERAS) program is crucial for achieving early recovery after surgery and continuous monitoring is essential for obtaining good results. This study aimed to describe the development and validation of a mobile app for enhanced recovery after surgery (MobERAS), a gamified mobile health app for telemonitoring patients in the postoperative period based on the ERAS program, and to evaluate its functionality and usability and the experience of patients, health care professionals, and computer professionals with its use. We developed MobERAS for postoperative telemonitoring, with active participation of patients in the process, and offering availability of real-time information for the health team. The app development process included idealization, interdisciplinary team formation, potential needs assessment, and product deployment. Usability tests were conducted throughout the development process with improvements, technical adjustments, and updates. After finalization, comprehensive verification tests were performed. The parameters evaluated are those that can influence the length of hospital stay, such as nausea, vomiting, pain scales, return to normal gastrointestinal function, and thromboembolic events. MobERAS was designed to be downloaded by users on their phones, tablets, or other mobile devices and to provide postoperative data. The app has a GPS that monitors the patient's walking time and distance and is connected to a virtual database that stores the collected data. Women undergoing medium and major gynecologic oncologic surgeries were included. We included 65 patients with an average age of 53.2 (SD 7.4, range 18-85) years. The time of use ranged from 23.4 to 70 hours (mean 45.1, SD 19.2 hours). Regarding adherence to the use of MobERAS, the mean fill rate was 56.3% (SD 12.1%, range 41.7%-100%), and ambulation data were obtained for 60 (92.3%) of the 65 patients. The researcher had access to the data filled out by the patients in real time. There was good acceptance of the use of MobERAS by the patients, with good evaluation of the app's usability. MobERAS was easy to use and considered attractive because of its gamified design. The app was rated as good or very good in all items by health care professionals (n=20) and professionals specializing in technological innovation (n=10). MobERAS is easy to use, safe, well accepted by patients, and well evaluated by experts. It can be of great use in clinical surgical practice and an important tool for greater engagement of patients and health care professionals with the ERAS program.

Embedded UUV conformal MEMS vector hydrophone

As the core equipment of Underwater acoustic detection, MEMS vector hydrophones are applied to Unmanned Underwater Vehicles (UUV), which can better detect underwater targets. Most of the MEMS vector hydrophones currently used are long-tube cylindrical, relatively large in volume and weight, which is not suitable for installation on UUV. The co-vibration vector hydrophone is small in size and weight, but it needs elastic suspension due to the requirements of the working principle. Therefore, according to the needs of practical engineering applications, this paper designs an Embedded UUV Conformal MEMS Vector Hydrophone (ECVH), establishes an encapsulation model through theoretical analysis, and uses COMSOL6.0 to simulate its acoustic performance. The sensitivity and directionality of the ECVH are verified in the standing wave barrel. When the test frequency is 630 Hz, the sensitivity of the vector channel is −182.3 dB, and the depth of the ' 8 ' direction concave point is greater than 35 dB. The sensitivity of the sound pressure channel is −182 dB, which is omnidirectional. Finally, it is mounted on UUV for preliminary signal acquisition verification test. The test results show that the ECVH can work normally on UUV, which provides a new idea for underwater small platform test.

(Invited) Growing Production Capacity in PEM Electrolysis: Learnings and Technical Accomplishments

Development of hydrogen production capacity with low carbon intensity (low carbon dioxide emissions) is an essential part of reaching global sustainability targets and mitigating long term climate change. While electrolysis has been commercial for decades, many applications have been smaller scale, and only a small fraction of the total hydrogen production is made from water rather than methane. In the US, there have also now been 7 Hubs selected which each have minimum targets of 50 metric tons of low carbon hydrogen production per day. The only way to meet these capacities in the near term is with proven commercial technologies such as liquid alkaline and proton exchange membrane (PEM) electrolysis. However, even though PEM technology has been commercial for decades, it has only recently reached megawatt scale, and most “gigafactories” that have been announced are not completely built out or staffed for these demands. It is therefore essential that PEM developers scale manufacturing capacity of cell stacks significantly in the next few years.Experience in commercial installations, manufacturing, and previous scale up are critical to success. Nel Hydrogen US has successfully scaled up cell stack active area by almost 2 orders of magnitude from its earliest products, and has gained decades of real world experience in how different field operation can be from controlled internal tests. The smaller platforms also offer built in verification testing for new designs and manufacturing methods. This talk will discuss Nel’s stack scale up journey, as well as updates on current expansion efforts.

Design and Parameter Optimization of a Combined Rotor and Lining Plate Crushing Organic Fertilizer Spreader

To address the inefficient crushing of fertilizer during the mechanized spreading process caused by the caking of high-humidity organic fertilizer, a fertilizer spreader with a combined rotor and lining plate crushing mechanism was proposed in this paper. With the introduction of the basic structure and working principle of the spreader, a particle group model for an organic fertilizer consisting of both caked and bulk fertilizer was built, based on the Hertz–Mindlin model with bonding and the Hertz–Mindlin model with JKR contact, in EDEM to construct an organic fertilizer-crushing-and-spreading model. With the rotor speed, the axial distance of the hammer, and the number of circumferential hammer groups as the experimental factors and the maximum broken bond rate of the caked organic fertilizer and the minimum coefficient of variation of spreading uniformity as the experimental indices, the Box–Behnken test method was employed to establish regression equations for response surface analysis and multi-objective optimization of the test results. The results indicated that, when the rotor speed was 6.47 Hz, the axial distance of the hammer was 90.30 mm, the number of circumferential hammer groups was five, the broken bond rate reached 90.86%, and the coefficient of variation was 21.45%. Verification tests under these conditions showed a broken bond rate of 90.03% and a coefficient of variation of 22.12%, which were consistent with the optimization results. Therefore, our research provides a reference for the structural design of an organic fertilizer spreader and the optimization of its working parameters.

Impact of heat treatment on the flavor stability of Longjing green tea beverages: Metabolomic insights and sensory correlations

The flavor stability of tea beverages during storage has long been a concern. The study aimed to explore the flavor stability of Longjing green tea beverage using accelerated heat treatment trials, addressing the shortage of lengthy storage trials. Sensory evaluations revealed changes in bitterness, umami, overall harmonization, astringency, and ripeness as treatment duration increased. Accompanied by a decrease in L-values, ΔE and an increase in a and b-values. Seventeen non-volatile metabolites and three volatile metabolites were identified differential among samples by metabolomics, with subsequent correlation analysis indicating associations between sensory attributes and specific metabolites. Umami was linked to epigallocatechin 3,5-digallate and alpha-D-glucopyranose, astringency was correlated with ellagic acid and 1-ethyl-1H-pyrrole. Ripeness showed associations with ellagic acid, 6,7-dihydroxycoumarin, heptanal, and benzaldehyde, and overall harmonization was linked to 6,7-dihydroxycoumarin, β-myrcene, α-terpineol, and heptanal. A series of verification tests confirmed the feasibility of accelerated heat treatment trials to replace traditional storage trials. These results offer valuable insights into unraveling the complex relationship between sensory and chemical profiles of green tea beverages.

A piezoelectric MEMS microphone with proof mass and its array

Piezoelectric MEMS microphones (PMMs) have attracted increased attention in home automation, wearable devices and autonomous driving, since the high linearity, dustproof and waterproof, and easy manufacturing. In this paper, a hexagonal PMM with proof mass and its array in parallel are proposed using a 20 % Scandium-doped Aluminum Nitride (ScAlN) thin film on a Silicon-on-insulator (SOI) wafer. The theoretical analysis, simulation, fabrication and verification test were discussed. The performance of the devices was simulated using the finite element simulation, and the resonant frequency is 102.85 kHz. The sensitivity of element and its array were measured up to −68.3 dB and −68.4 dB, respectively (re: 1 V/Pa). And the sensitivities of the element and array were −38.6 dB and −37.9 dB at 1 kHz (re: 1 V/Pa) after amplification and filtering. The SNR of the array was increased to 55.3 dB since the increased capacitance of array. Besides, the total harmonic distortion (THD) was measured 1.7 % and 1.14 %, respectively. The PMM and its array with high SNR and good THD is suitable to commercial acoustic fields, especially the high-noise scenarios.

Rated flow coefficient of geometric compensation control valve

Abstract Aiming at the large design error of the rated flow coefficient of existing control valves, it was difficult to meet the requirements of the equipment system. This study adopts the principle of infinite approximation to the existing flow coefficient calculation equation for geometric shape correction compensation, based on which the rated flow coefficient design method was proposed, and simulation and test verification were carried out. The results show that according to the design method, the rated flow coefficient of the control valve can be accurately designed. The variation rule of the simulated value and the test value under the two kinds of spool inner parts is consistent, and the maximum error is not more than 10%, which meets the requirements of industrial standards. The experiment verifies the accuracy and applicability of the design method.

Consistency and repeatability verification for vehicle in the loop test platform based on digital twin of proving ground

Abstract A high-confidence vehicle-in-the-loop test method based on the digital twin of proving ground (DTPG-VIL) is proposed for the test of autonomous driving vehicles. The overall architectural design of the DTPG-VIL and the corresponding components are introduced, with a focus on describing the scene simulation system based on the digital twin of the proving ground. A King Long intelligent driving sightseeing bus for test verification is introduced, and its positioning performance is verified by the high-definition positioning base station and GPS/INS combined navigation system to verify the accuracy of its positioning precision and meet the requirements of the digital twin test so that the DTPG-VIL can obtain more information from the bus. Taking the automatic emergency avoidance function as an example, the method, process, and experimental results of the control test between the DTPG-VIL test and the real vehicle test in a proving ground are designed. Through the correlation coefficient analysis and transient response analysis, consistency and repeatability comparisons are carried out to verify the high confidence of the digital twin test.

Attracting IT Talent: A Kano Analysis of Employer Attributes

Recruiting information technology (IT) talent remains a pressing issue for employers. Organizations therefore work on enhancing and highlighting their attractiveness. Drawing on the theory of attractive quality, the Kano model, we empirically investigate attributes that specifically attract IT talents in a recruiting context. Based on 30 interviews and a survey of 301 IT professionals and IT students, we identify and evaluate 24 attractiveness attributes that are further classified according to the nature of their role in attracting IT talent. The attribute identification and evaluation involve several steps including categorization, significance, and verification testing. Our research introduces Kano analysis as a useful tool to elicit nontrivial preference portfolios relevant to the IT job market. The empirical results add to the IT workforce literature and offer a concrete classification of what attributes employers should or even need to provide to recruit these scarce talents. The analysis also discloses differences in the survey participants' work experience and gender. Organizations can use the method to develop more effective candidate communication and reveal weak spots in their employer branding efforts.